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// SPDX-License-Identifier: GPL-2.0
/* Use /dev/watch_queue to watch for notifications.
*
* Copyright (C) 2019 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <stdbool.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#include <errno.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <poll.h>
#include <limits.h>
#include <linux/watch_queue.h>
#include <linux/unistd.h>
#include <linux/keyctl.h>
#ifndef KEYCTL_WATCH_KEY
#define KEYCTL_WATCH_KEY -1
#endif
#ifndef __NR_watch_devices
#define __NR_watch_devices -1
#endif
#define BUF_SIZE 4
static long keyctl_watch_key(int key, int watch_fd, int watch_id)
{
return syscall(__NR_keyctl, KEYCTL_WATCH_KEY, key, watch_fd, watch_id);
}
static const char *key_subtypes[256] = {
[NOTIFY_KEY_INSTANTIATED] = "instantiated",
[NOTIFY_KEY_UPDATED] = "updated",
[NOTIFY_KEY_LINKED] = "linked",
[NOTIFY_KEY_UNLINKED] = "unlinked",
[NOTIFY_KEY_CLEARED] = "cleared",
[NOTIFY_KEY_REVOKED] = "revoked",
[NOTIFY_KEY_INVALIDATED] = "invalidated",
[NOTIFY_KEY_SETATTR] = "setattr",
};
static void saw_key_change(struct watch_notification *n)
{
struct key_notification *k = (struct key_notification *)n;
unsigned int len = (n->info & WATCH_INFO_LENGTH) >> WATCH_INFO_LENGTH__SHIFT;
if (len != sizeof(struct key_notification) / WATCH_LENGTH_GRANULARITY)
return;
printf("KEY %08x change=%u[%s] aux=%u\n",
k->key_id, n->subtype, key_subtypes[n->subtype], k->aux);
}
static const char *block_subtypes[256] = {
[NOTIFY_BLOCK_ERROR_TIMEOUT] = "timeout",
[NOTIFY_BLOCK_ERROR_NO_SPACE] = "critical space allocation",
[NOTIFY_BLOCK_ERROR_RECOVERABLE_TRANSPORT] = "recoverable transport",
[NOTIFY_BLOCK_ERROR_CRITICAL_TARGET] = "critical target",
[NOTIFY_BLOCK_ERROR_CRITICAL_NEXUS] = "critical nexus",
[NOTIFY_BLOCK_ERROR_CRITICAL_MEDIUM] = "critical medium",
[NOTIFY_BLOCK_ERROR_PROTECTION] = "protection",
[NOTIFY_BLOCK_ERROR_KERNEL_RESOURCE] = "kernel resource",
[NOTIFY_BLOCK_ERROR_DEVICE_RESOURCE] = "device resource",
[NOTIFY_BLOCK_ERROR_IO] = "I/O",
};
static void saw_block_change(struct watch_notification *n)
{
struct block_notification *b = (struct block_notification *)n;
unsigned int len = (n->info & WATCH_INFO_LENGTH) >> WATCH_INFO_LENGTH__SHIFT;
if (len < sizeof(struct block_notification) / WATCH_LENGTH_GRANULARITY)
return;
printf("BLOCK %08llx e=%u[%s] s=%llx\n",
(unsigned long long)b->dev,
n->subtype, block_subtypes[n->subtype],
(unsigned long long)b->sector);
}
static const char *usb_subtypes[256] = {
[NOTIFY_USB_DEVICE_ADD] = "dev-add",
[NOTIFY_USB_DEVICE_REMOVE] = "dev-remove",
[NOTIFY_USB_DEVICE_RESET] = "dev-reset",
[NOTIFY_USB_DEVICE_ERROR] = "dev-error",
};
static void saw_usb_event(struct watch_notification *n)
{
struct usb_notification *u = (struct usb_notification *)n;
unsigned int len = (n->info & WATCH_INFO_LENGTH) >> WATCH_INFO_LENGTH__SHIFT;
if (len < sizeof(struct usb_notification) / WATCH_LENGTH_GRANULARITY)
return;
printf("USB %*.*s %s e=%x r=%x\n",
u->name_len, u->name_len, u->name,
usb_subtypes[n->subtype],
u->error, u->reserved);
}
/*
* Consume and display events.
*/
static int consumer(int fd, struct watch_queue_buffer *buf)
{
struct watch_notification *n;
struct pollfd p[1];
unsigned int head, tail, mask = buf->meta.mask;
for (;;) {
p[0].fd = fd;
p[0].events = POLLIN | POLLERR;
p[0].revents = 0;
if (poll(p, 1, -1) == -1) {
perror("poll");
break;
}
printf("ptrs h=%x t=%x m=%x\n",
buf->meta.head, buf->meta.tail, buf->meta.mask);
while (head = __atomic_load_n(&buf->meta.head, __ATOMIC_ACQUIRE),
tail = buf->meta.tail,
tail != head
) {
n = &buf->slots[tail & mask];
printf("NOTIFY[%08x-%08x] ty=%04x sy=%04x i=%08x\n",
head, tail, n->type, n->subtype, n->info);
if ((n->info & WATCH_INFO_LENGTH) == 0)
goto out;
switch (n->type) {
case WATCH_TYPE_META:
if (n->subtype == WATCH_META_REMOVAL_NOTIFICATION)
printf("REMOVAL of watchpoint %08x\n",
(n->info & WATCH_INFO_ID) >>
WATCH_INFO_ID__SHIFT);
break;
case WATCH_TYPE_KEY_NOTIFY:
saw_key_change(n);
break;
case WATCH_TYPE_BLOCK_NOTIFY:
saw_block_change(n);
break;
case WATCH_TYPE_USB_NOTIFY:
saw_usb_event(n);
break;
}
tail += (n->info & WATCH_INFO_LENGTH) >> WATCH_INFO_LENGTH__SHIFT;
__atomic_store_n(&buf->meta.tail, tail, __ATOMIC_RELEASE);
}
}
out:
return 0;
}
static struct watch_notification_filter filter = {
.nr_filters = 3,
.__reserved = 0,
.filters = {
[0] = {
.type = WATCH_TYPE_KEY_NOTIFY,
.subtype_filter[0] = UINT_MAX,
},
[1] = {
.type = WATCH_TYPE_BLOCK_NOTIFY,
.subtype_filter[0] = UINT_MAX,
},
[2] = {
.type = WATCH_TYPE_USB_NOTIFY,
.subtype_filter[0] = UINT_MAX,
},
},
};
int main(int argc, char **argv)
{
struct watch_queue_buffer *buf;
size_t page_size;
int fd;
fd = open("/dev/watch_queue", O_RDWR);
if (fd == -1) {
perror("/dev/watch_queue");
exit(1);
}
if (ioctl(fd, IOC_WATCH_QUEUE_SET_SIZE, BUF_SIZE) == -1) {
perror("/dev/watch_queue(size)");
exit(1);
}
if (ioctl(fd, IOC_WATCH_QUEUE_SET_FILTER, &filter) == -1) {
perror("/dev/watch_queue(filter)");
exit(1);
}
page_size = sysconf(_SC_PAGESIZE);
buf = mmap(NULL, BUF_SIZE * page_size, PROT_READ | PROT_WRITE,
MAP_SHARED, fd, 0);
if (buf == MAP_FAILED) {
perror("mmap");
exit(1);
}
if (keyctl_watch_key(KEY_SPEC_SESSION_KEYRING, fd, 0x01) == -1) {
perror("keyctl");
exit(1);
}
if (syscall(__NR_watch_devices, fd, 0x04, 0) == -1) {
perror("watch_devices");
exit(1);
}
return consumer(fd, buf);
}
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